BDNF and major depressive disorder: The implication of dysregulated BDNF in depression is also supported by both human post-mortem (Duman and Li, 2012) and rodent (McEwen, 2007; Castrén and Rantamäki, 2010) studies, showing that human depression and rodent models of depression are associated with decreased expression of several neurotrophic factors, including BDNF.